The present invention relates to resolver apparatus for receiving an electrical input signal representing a vector quantity and generating an electrical output signal corresponding to the vector quantity rotated through a given angle. In particular, the invention comprises fine and coarse-angle solid-state resolvers which are cascaded to provide resolver apparatus having excellent resolution and low error.
Broadly defined, a resolver is a computing device which resolves an input vector into two orthogonal components in the plane of the input vector. Resolvers may also be used to effect the rotation of an input vector through a desired angle to produce an output vector angularly displaced from and coplanar with the input vector.
Typically, the resolver is an electro-mechanical device comprising input and output windings rotatable with respect to each other by positioning a shaft attached to one set of windings. Analog voltages corresponding to the orthogonal components of the input vector are applied to the input windings and the shaft is mechanically rotated through the desired angle to produce voltages at the output windings corresponding to the orthogonal components of the rotated input vector.